1. Field
The invention is in the field of couplings to connect plain end and grooved end pipes, and pipes having shoulders in their end portions, and couplings used to connect pipes with valves and dead ends in piping systems.
2. State of the Art
Plain end couplings under the names of Norma Normaconnect and Straub Pipe Joints are currently in use to join two plain end pipes. A grooved end coupling, under the name of Victaulic Coupling is used to join grooved end pipes. The above coupling is limited in its ability to be suitable to meet various needs of the pipe systems which transport fluids. The invented coupling is a multipurpose coupling, which can provide a restrained joint between two ends of pipes having grooves or shoulders in the end portions of said pipes, or an unrestrained joint for plain end pipes without having said grooves or shoulders in the end portion of pipes. The invented coupling can also provide a restrained joint on its one end, while providing an unrestrained joint on its other end. The invented coupling is made of two pieces, where, in most applications, each piece is a mirror view of the other piece. Each piece houses means which surround the pipe to hold the pipe inside the coupling. If the downstream pipe is of a different size than, and if it is made from different material than, the upstream pipe, then the design and size of the down stream piece of the invented coupling is adjusted and modified. To prevent the pipes from slipping from the coupling, the invented coupling, inside of its body, is fitted with a removable centrally located partitioning washer ring incorporated between said two pieces. Once the pipe is installed, said partitioning ring, located at the center of the coupling body, allows only limited movement of the pipes inside of the body of the coupling, and thus prevents migration of the coupling with respect to the pipe, and therefore also prevents the ends of the pipes from being pulled out from the coupling body. The invented coupling is provided with a centrally located interlocking, doubled-up mechanical mechanism means, comprised of two mechanisms, where each mechanism performs its intended function in sequence to connect two said pieces of the coupling body, and to secure the coupling to the ends of two pipes. The invented coupling can be split axially into two pieces. Said doubled-up mechanism can also be used to join two split bodies of valves which split axially, as valves invented by the inventor under patent numbers U.S. Pat. Nos. 6,672,334 B2 and 5,715,857. It can also be used to connect dead ends in the pipe system, and also valves and other fitting can be incorporated into the coupling between the ends of pipes being connected. Compared to other compression couplings, which are comprised of a sleeve situated between two flanges, where said sleeve and flanges are secured with bolts, the invented coupling can be secured to the ends of pipes much more quickly, with the use of far fewer bolts in the case of large size pipes (six inch, and larger pipe). Therefore, the invented coupling can also release the pipes more quickly than said compression couplings, for large pipe sizes. The first part of said interlocking doubled-up mechanism of the invented coupling is comprised of two secondary flanges m1 and m2, which are constructed farthest away from the radial center plane M3 of the coupling on the corresponding outer rims of the main flanges M1 and M2. The main flanges are held together face to face around the radial plane M3 of the coupling body. The secondary flanges are connected together by means of bolts and nuts to match the intermittent radial shoulders 12 and 12A constructed around the opposite main flanges M1 and M2. The second part of the doubled-up mechanism is made of a cover means provided with intermittent inner radial shoulders 14 and 14A in its end portions, which can be simultaneously rotated between said two secondary flanges m1 and m2 and intermittent radial shoulders 12 and 12A constructed around said two main flanges M1 and M2. Once the inner radial intermittent shoulders 14 and 14A of the cylindrical cover are positioned against the intermittent shoulders 12 and 12A in the locking position, shoulders 14 and 14A can then be locked in position by means of at least a single bolt and nut, and the coupling is secured to the two end portions of the pipes. The coupling can accommodate the predetermined shrinkage (the Poisson's effect) in the lengths of each link of pipe, and their thermal expansion and contraction. The doubled-up mechanism makes the coupling versatile to meet various needs of the piping system. From here on, “end of pipe”, “end of valve”, and “dead end”, will be considered as synonymous in meaning. The following are the objectives of the invented coupling: (1) The first object of the invention is to provide a centralized separable interlocking doubled-up coupling mechanism for the coupling, by which the coupling joins two ends of opposite pipes of the same size, or pipes of different sizes, made from the same type of material, or pipes which are made from different types of materials. (2) The second object of the invention is to provide a coupling such that at least one of the two pieces of the coupling body housing inner means can be used to connect two pipes. (3) The third object of the invention is to provide a coupling where said inner means which surrounds and holds the end portion of pipe inside of coupling body, are modifiable, and include pipe inserts and seal gaskets. (4) The fourth object of the invention is to provide a coupling which can accommodate the shrinkage (the Poisson's effect) of each link of pipe. (5) The fifth object of the invention is to provide a coupling which can accommodate the change in the length of pipe due to thermal effect. (6) The sixth object of the invented coupling is that each end portion of the coupling body beyond the secondary flanges m1 and m2 be modifiable, while retaining the same doubled-up mechanism in all cases. (7) The seventh object of the invention is to provide a partitioning means incorporated between said two pieces of coupling, whereby the coupled pipes are prevented from being pulled out from the coupling body. (8) The eight object of the invention is to provide a coupling where each half of the coupling body can be axially parted into two pieces, and said two pieces can be assembled or disassembled around the pipe. From here on, the coupling body will be understood to have two pieces, and each of the two pieces can be monolithic in structure or can be a structure which can be axially separated into two parts.